1. Field of the Invention
The present invention relates to a drum washing machine, and more particularly, to a drum washing machine having a washing water circulation unit improving washing efficiency by spraying washing water contained in a fixed drum to a central portion of a rotatable drum.
2. Description of the Related Art
In general, a drum type washing machine is an appliance intended to carry out a washing operation by falling washing water during rotation of a rotatable drum. The drum washing machine includes a hexahedral housing, a fixed drum suspended in the hexahedral housing containing the washing water, the rotatable drum disposed in the fixed drum to rotate in forward and reverse directions, and a shock absorbing member supporting the fixed drum within the hexahedral housing.
In the drum washing machine, washing, rinsing and dehydrating operations are automatically carried out in accordance with a previously inputted program while the rotatable drum rotates. The washing operation carried out by the drum washing machine can be classified into one of a stain washing operation for stained laundry, a standard washing operation, and a wool washing operation for wool laundry according to types of laundry. However, the conventional drum washing machine is limited in washing efficiency because the washing and rinsing operations are achieved only by falling washing water during rotation of the rotatable drum.
To overcome the above problems, the applicant filed a Korean Utility Model Application No. 1997-11762, which has been published in Korean Laid-open No. 1998-67224, describing a washing water circulation unit spraying washing water on a rotatable drum by forcibly pumping the washing water contained in a fixed drum.
As shown in FIG. 1, a washing water circulation unit in a drum washing machine disclosed in the published specification of the above Korean Utility Model Laid-open No. 1998-67224 includes spray nozzles 3 spraying the washing water collected in a bottom of a tub or fixed drum 2 and pumped upward by a drainage pump 1, a first solenoid valve 4 disposed adjacent to the spray nozzles 3 and designed to be closed during a drainage operation and to be opened during a washing operation, a water circulation hose 6 connected at one end to the spray nozzles 3 and connected at the other end to a T-shaped connector 7 coupled between the drainage pump 1 and the drainage hose 5, and a second solenoid valve 8 disposed at an inlet of the drainage hose 5 and designed to be closed during the washing operation.
The spray nozzles 3 are disposed above an upper surface of the tub 2 in order to spray the washing water through a plurality of holes 9a formed at the wall of a rotatable drum 9. The second solenoid valve 8 prevents the washing water pumped by the drainage pump 1 from being drained through the drainage hose 5 during the washing operation. A reference numeral 13 denotes a door unit.
Accordingly, when the drainage pump 1 is activated while the washing operation is carried out by rotation of the rotatable drum 9, the washing water in the tub 2 is pumped to the upper surface of the tub 2 and then sprayed downward therefrom.
That is, the washing water pumped by the drainage pump 1 is guided to the spray nozzles 3 through the water circulation hose 6 and then sprayed into the rotatable drum 9 through holes 9a, thereby improving washing efficiency and solubility of detergent.
However, since the washing water sprayed through the spray nozzles 3 first impinges against an outer wall of the rotatable drum 9, only a small amount of the sprayed washing water can be sprayed into the rotatable drum 9 through the holes 9a and thus a large amount of the water flows downward along the outer wall of the rotatable drum 9 and returns to the tub 2.
Therefore, although the solubility of the detergent may be improved by circulation of the washing water, there is a limited improvement in the washing efficiency by the sprayed washing water. In addition, since the pump 1 must be operated even during the washing operation, power consumption is increased.
Accordingly, the present invention has been made to overcome the above and other problems of the related art, and an object of the present invention is to provide a drum washing machine with an improved washing water circulation unit which is adapted to directly spray washing water contained in a fixed drum into an inside of a rotatable drum during a washing operation so as to enhance washing efficiency and solubility of detergent.
It is another object of the present invention to provide a drum washing machine which is adapted to draw washing water contained in a fixed drum by a turning force of a rotatable drum and to spray the washing water into the rotatable drum.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
In order to achieve the above and other objects, the present invention provides a drum washing machine including a housing, a fixed drum disposed in the housing and containing washing water, a rotatable drum rotatably disposed in the fixed drum, and a circulation unit supplying the washing water contained in the fixed drum to an inside of the rotatable drum, the circulation unit including a drawing unit drawing the washing water upwardly toward a central portion of a rear panel of the rotatable drum by a turning force of the rotatable drum, and a spray unit spraying the washing water into the inside of the rotatable drum, the spray unit disposed at the rear panel of the rotatable drum.
The drawing unit is disposed at the rear panel of the rotatable drum and is provided with a curved water-guiding duct connected at one end with the spraying unit, then extended to a periphery of the rear panel therefrom, and connected at the other end with the fixed drum.
The curved water-guiding duct unit includes first water-guiding ducts drawing the washing water during a forward rotation of the rotatable drum, and second water-guiding ducts drawing the washing water during a reverse rotation of the rotatable drum.
The first water-guiding ducts form a first pair symmetrical to each other and around the spraying unit, and the second water-guiding ducts form a second pair symmetrical to each other and around the spraying unit.
The spraying unit is located at the center portion of the rear panel of the rotatable drum and is provided with a nozzle which is formed with a plurality of holes to allow the washing water drawn by the drawing unit to be sprayed therethrough.
The washing water introduced through the first and second water-guiding ducts is sprayed through the holes of the spray unit, and an interior space of the spray unit is divided into a plurality of subspaces using a partition so as to prevent the first and second water-guiding ducts from communicating with each other.